title: l-Serine induces sedative and hypnotic effects acting at GABA(A) receptors in neonatal chicks.
abstract: Intracerebroventricular injection of l-serine has been shown to have sedative and hypnotic effects on neonatal chicks exposed to acute stressful conditions. However, the mechanism by which l-serine induces these effects is unclear. The present study was conducted to clarify the mechanism by l-serine. The involvement of gamma-aminobutyric acid (GABA)(A) receptors on the effect of l-serine was investigated using the GABA(A) receptor antagonist picrotoxin. Co-administration of picrotoxin attenuated the sedative and hypnotic effect of l-serine. Further, we also investigated the involvement of glycine receptors since l-serine is suggested to act as the alpha-homomeric glycine receptor agonist. Glycine similarly induced sedative and hypnotic effects in chicks, but its effect was attenuated by the glycine receptor antagonist strychnine. Therefore, whether the effect of l-serine was mediated through the glycine receptor was investigated using l-serine and strychnine. The effect of l-serine was inhibited by picrotoxin, but not strychnine. It appears that l-serine induces sedative and hypnotic effects by enhancing inhibitory neurotransmission via GABA(A) receptors.
authors.affiliation: Laboratory of Advanced Animal and Marine Bioresources, Graduate School of Bioresources and Bioenvironmental Sciences, Kyushu University, Fukuoka 812-8581, Japan.
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Shigemi
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Tsuneyoshi
authors.forename: Kousuke
authors.initials: K
authors.lastname: Hamasu
authors.forename: Li
authors.initials: L
authors.lastname: Han
authors.forename: Kohsuke
authors.initials: K
authors.lastname: Hayamizu
authors.forename: D Michael
authors.initials: DM
authors.lastname: Denbow
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Furuse
mesh_terms: D000208:Acute Disease; D000818:Animals; D000831:Animals, Newborn; D002645:Chickens; D004195:Disease Models, Animal; D005998:Glycine / Q000494:pharmacology; D006993:Hypnotics and Sedatives / Q000494:pharmacology*; D008297:Male; D010852:Picrotoxin / Q000494:pharmacology; D011963:Receptors, GABA-A / Q000187:drug effects* / Q000378:metabolism; D018009:Receptors, Glycine / Q000187:drug effects / Q000378:metabolism; D012694:Serine / Q000494:pharmacology*; D013315:Stress, Psychological / Q000378:metabolism
chemical_list: D005998:Glycine; D006993:Hypnotics and Sedatives; D010852:Picrotoxin; D011963:Receptors, GABA-A; D018009:Receptors, Glycine; D012694:Serine